The present invention is directed toward a lateral flow immunoassay device and more particularly, toward a test device that allows the sample to be treated and incubated prior to being introduced to the test strip.
Immunoassay devices utilizing immunochromatography are often single step devices where a test sample is analyzed for the presence of certain analytes. For example, a specified volume of the sample is contacted with one end of a test strip. The test strip contains colored particles coated with a binder dried on the strip. As the sample is wicked up the test strip, the analyte in the sample reacts with the binder coated on the particles. The test strip also contains antigens in discrete zones. As the reaction mixture flows up the strip, any reaction between the antigens and the analyte, if present, may be observed by the appearance or non-appearance of color in the zones. Often, such tests are used in drug screening.
There are several disadvantages to the system described above. For example, once the test sample is introduced, there is no user control over the subsequent events. That is, the fluid flow determines the speed and timing of all of the reactions. Also, if the sample requires pre-treatment with specific reagents to dilute or denature interferants, modify analyte structure, or release analyte from binders, such treatments must be performed outside of the confines of the test device. Therefore, a need exists for a self-contained and simple to use test device that allows control over the test sample so that more accurate test results may be obtained.